FDA-approved biosimilar insulin: good enough for critical care, adulterated, or counterfeit? How can we tell?

If a biosimilar insulin is discovered postmarketing to be subpotent, superpotent, or contaminated or the contents mislabeled, it is an adulterated product and must be quarantined for removal including from a patient's home. Adulterated products could be considered "counterfeit" since they do not meet the original standards established by the FDA. The FDA must establish a method of regularly assaying samples of biosimilar insulin drawn directly from the supply pipeline to help ensure patient safety and evaluate clinical performance. Independent groups without conflict of interest would perform confidential comparison assay. For less than 5 cents per vial/pen, manufacturers could easily support an independent, FDA-recognized, random sample program and create a functional postmarket surveillance system that better protects the public and the manufacturer from undesired outcomes.